FOREST CONSERVATION

Evening Star, Issue 23833, 13 March 1941, Page 11

FOREST CONSERVATION

LESSONS FOR NEW ZEALAND MAHER OF IMMEDIATE CONCERN Appropriately placed native forests are a country’s greatest asset; for the forest is the greatest preserver of the soil, and our very existence depends on the soil and its continued fertility (writes “ Lucretius,” in ‘ Forest and Bird,’ the official organ of the New Zealand Forest and Bird Protection Society). Many past civilisations have perished as a direct result of wanton destruction of their forests. Who hashiot seen pic-, tures of the ruins of fine cities in North Africa, Asia Minor, Persia, China, etc., etc.? Did Darius, the great Persian conqueror, build his huge palace at Persepolis in an uninhabited waste. China 2,500 years ago had abundant forests; to-day wood is very scarce indeed in China, such forces as remain are being confined to almost inaccessible mountains. Destruction of the forest in the catchment areas of the ancient Mesopotamian irrigation system, the finest ever known, resulted in the formation of desert. The Mediterranean countries all show striking evidence of the dire results following deforestation. In Karst, for instance, naked rocks are found where once was forest. The country knows nothing but drought, all the rain that falls being lost in rock fissures or evaporated from the hot rock.

Until 1852 the foothills of the Himalayas in the Punjaub were used as hunting grounds and were covered in forest. In that year the British annexed the Punjaub and handed over these foothills to the villagers. , Fire, the axe, and the goat soon destroyed tho vegetation. This area is now an oft-quoted example of the effects of accelerated erosion—a fertile wooded land which 50 years later was wellnigh. useless. The French Niger Colony is now largely desert, but 200 years ago this huge tract of land had forests and its people were prosperous. Innumerable other examples of the consequences of spoliation of the forests might be drawn from Africa, Asia, America, and Australia. No continent has not suffered.

In New Zealand the impoverishment of our native forest resources by fire and improper management is a matter of immediate concern; it is the concern not only of the timber merchants, hut of manufacturers, bankers, farmers, and, indeed, every one of us. Already in this country, barely 100 years old in white man’s history, far too much of it has gone. It behoves us not to he heedless of the lesson of tho Punjaub and other places where the forest has been destroyed. . Soil eroded is soil lost, maybe for ever. But it is well to remember that tho soil, with its bacterial and other minute life, the vegetative covering, and the animals living therein, constitute one whole, whose parts cannot, be considered as separate entities. Vegetation certainly grows on the soil, yet were it not for vegetation there would be no soil. Soil consists of more than disintegrated rock and water; it has an organic part, the humus, derived •mostly-'from decayed vegetation.”' ■ All vegetation helps to form soil and to protect it from being washed away bv excessive rainfall or being blown away by wind, but the best form of vegetal ion for protecting the soil is forest in its natural condition, especially where the terrain is rough. ‘trees, as everyone knows, act as protection against wind, but their action against other erosive agents is not so well known.

The canopy of leaves and branches prevents the beating effect of rain falling directly on the soil. Leaves drip for as long as an hour or more after rain Las ceased falling. Dew and mist condensing on the leaves act in a similar manner.

When the water has dripped from the leaves it falls on to the litter of leaves and other debris on the forest floor. This litter, together with the underlying humus, absorbs the water, preventing a rapid run-off, and gradually passes it down to the deeper layers of soil and subsoil, where it is held as an underground reservoir. A large quantity of the underground water is absorbed by the roots and returned to the atmosphere as vapour from the leaves, but most of it seeps through the soil to the streams.

Streams arising in forested regions remain clear, and their water content does not vary much throughout the year. Thus it is that forests are the great controller _of floods, and by far the least expensive. It is very essential, therefore, that all high country clothed in natural native vegetation should promptly be declared inviolate reservations. And now that summer is here, the bush fire is also here. Let people be careful not to start fires which might spread to forest or other vegetative covering of the soil. Fire, by destroying forest cover, causes excessive water run-off and spells destruction to all forms of wild life. It kills trees and thus destroys the protective canopy. Those trees it does not kill it damages, and insect pests complete the ruin. It burns the undergrowth. the invaluable litter on the forest floor, and destroys the underlying humus. When the covering is burnt off the soil is exposed and unprotected, so that it soon dries out, its structure and life are destroyed, and it seriously erodes when rain falls or tho wind blows. Water is no longer absorbed, but runs off rapidly, an agent of destruction. Silt-laden streams contain little or no aquatic life, tho silt is deposited where it is not required, the bod of the stream is raised when tho velocity of tho water is lowered, floods are caused, etc. .One small fire might cause untold damage if allowed to spread. New Zealanders, don’t let your forests burn, keep them growing! They protect the soil, from which we derive our nourishment, and which is our country’s and our Empire’s first line of defence. New Zealanders should bear in mind what happened in France when the forest protecting the headwaters of many of their important rivers was destroyed. A few trees wantonly destroyed cost millions of francs and years of time to replace, and it was necessary for the wellbeing and safety of the people of France to have them replaced.